Semiconductor light emitting circuits may include one or more semiconductor Light Emitting Diodes (LEDs). As is well known to those having skill in the art, a light emitting diode includes a plurality of semiconductor layers that are configured to emit light upon energization thereof.
In order to increase the light output of a semiconductor light emitting circuit, it may be desirable to provide multiple LEDs in the circuit. Multiple LEDs may be connected in parallel. However, to reduce or prevent current hogging by one of the LEDs, it may be desirable to provide voltage matched LEDs. Unfortunately, voltage matched LEDs may increase the cost of the semiconductor light emitting circuit. In other semiconductor light emitting circuits, a plurality of LEDs are connected in a series string. Unfortunately, if one LED in the string fails and becomes an open circuit, the entire string may fail to light due to the open circuit.
It is known to shunt one or more Zener diodes across an LED, to provide electrostatic discharge (ESD) protection. See, for example, U.S. patent application Publication Nos. U.S. 2001/0032985 A1 to Bhat et al. and 2002/0139987 A1 to Collins, III et al., and European Patent Application No. EP 1 020 935 A2 to Maeda et al.